Bombardier Reassessing CSeries Flight-Test Schedule

Clean first flight for CSeries, but achieving service entry of all-new airliner in 12 months looks aggressive

Emerging from a hiatus in new-product development in 2008, Bombardier took on its biggest challenge yet—to enter a new market with a clean-sheet design, its largest aircraft ever and its first with fly-by-wire flight controls, carbon-fiber composite wing and geared-turbofan engines.

The Canadian manufacturer crossed its first hurdle on Sept. 16, when the CSeries narrowbody airliner made its delayed first flight from Mirabel, near Montreal. But with the focus shifting to service entry, assumptions made when the development program was laid out are being reexamined to see whether Bombardier can deliver the first aircraft as planned, a year from now.

First flight was scheduled for December, but was postponed to the end of June by assembly delays. It then slipped further as ground testing took longer than anticipated. So far, the company is sticking publicly to plans for a five-aircraft, 2,400-hr. test program leading to entry into service (EIS) of the initial 110-seat CS100 in 12 months, but its experience with ground tests is leading Bombardier to review its plans.

“We really need to reassess, to take another look at the scope of flight testing and how fast we can do it,” says Rob Dewar, vice president and general manager for CSeries. “Our focus has been on early entry into service, but the aircraft has to be mature and ready for EIS.” The reassessment “will take a couple of months” and require a few more flights, as well as discussions with CSeries customers, he says.

“Boeing laid out the 787 at 48 months, and it took close to eight years. We set our schedule at 5.5 years, and some thought that was too conservative. But aircraft are more integrated now, so there are more tests to do, and the rules are more challenging, which is new to us,” Dewar says, adding “We set the schedule [for first flight] too aggressively. It took longer than planned.”

Even with delays, there is still some cushion in the schedule before Bombardier would incur penalties for late delivery. Playing down the delay, Bombardier CEO Pierre Beaudoin says the internal target for first flight was June, so it was less than three months behind. Nico Buchholz, executive vice president of group fleet management for CSeries launch customer Lufthansa, says the EIS is still within the window of variability assumed in the carrier's planning.

Bombardier is holding to its projected $3.4 billion for development of the CSeries, although it now reports a total of $3.9 billion to include the $500 million in interest on financing its $2 billion share of the development cost, with the rest coming from suppliers and the Canadian, Quebec and U.K. governments.

Firm orders still stand at 177 aircraft, but will “definitely” reach the target of 300 by EIS, says Mike Arcamone, president of Bombardier Commercial Aircraft. Several customers are waiting for flight tests to confirm the performance projections, he says. Aircraft Nos. 2 and 4 are the performance-test vehicles. “Midway through flight test, will we have the majority of the performance data,” says Dewar.

The CSeries conducted its first flight in middle-of-the-envelope conditions, taking off at mid-weight and reduced thrust—which contributed to its extraordinary quietness. The aircraft reached 12,500-ft. altitude and 230-kt. airspeed, retracting the landing gear and varying flap and slat settings during a 2.5-hr. flight, says chief test pilot Chuck Ellis, who commanded flight-test vehicle 1 (FTV1).

There was one minor fault during the flight: an advisory message from one of the subsystems. “We made a small adjustment, and achieved all of our objectives,” Ellis says. Most of the extra time on the ground over the past weeks was spent testing and maturing the aircraft software. “A lot of the maturity work was around erroneous messages. We had one message on the flight, and there was no functionality issue. I was expecting five to 10, not just one,” says Dewar.

The CSeries is Bombardier's first fly-by-wire (FBW) aircraft, and FTV1's first flight was in the direct, or degraded mode that is the backup in the event of a flight-control failure. “We were very conservative, and by flying in a degraded mode were able to see the aircraft responding, not the FBW computers interacting. We were trying to remove that part of the equation,” Ellis says.

The FBW system will be switched to fully augmented normal mode for later flights. Bombardier's fly-by-wire control philosophy is “to give the pilots cues when the aircraft is approaching its limits, but allow them a bit more,” says Ellis. The CSeries also is the company's first aircraft with sidestick controllers. “We have soft and hard stops. But the aircraft is designed around the soft stops.”

The remaining four CS100 flight-test vehicles, the first production aircraft and the first test aircraft for the 130-/160-seat CS300 are in final assembly at Mirabel, but Bombardier will review the results from FTV1 before flying the next aircraft, in case changes are required. Modifications from ground testing have been rolled into FTV2-5. “Everything we learned on 1 we have put into 2-5. We could get two aircraft up fast, but there is no sense putting two in the air if we have to change them,” Dewar says.

Static structural testing has continued beyond the seven safety-of-flight cases required for first flight, with no issues so far with the aluminum-lithium fuselage and resin-transfer molded carbon-fiber wing. “We are tracking to plan,” says Dewar. Final assembly of the fatigue-test article has begun on site at IABG in Germany, where durability testing is expected to begin by year-end.

Test and initial production aircraft are being assembled at Mirabel, in a facility originally built for the smaller CRJ700 series. Construction of a dedicated CSeries assembly building will be completed by mid-2014, when production needs to move. The new building will have four fixed stations for joining of the fuselage sections and wing and mounting of the gear. Once on their wheels, aircraft join a moving assembly line for completion.

Production is beginning to ramp up, and is planned to reach a capacity of 120 aircraft a year by the end of 2016. China's Shenyang Aircraft, which already builds the rear fuselage section, is beginning assembly of the center and forward fuselage sections and will take over from Bombardier's Belfast, Northern Ireland, plant.

Dewar says Bombardier decided to build the airframe sections at its own plants to protect the program in its early stages, when there are a lot of design changes, then transition them when the work became more repetitive. “We know China can build the fuselages, no question. They have done well on the rear fuselage and are tracking well to the plan,” he notes.

The CSeries is the first aircraft powered by Pratt & Whitney's geared turbofan—a decision that was critical to meeting the aircraft's aggressive fuel-economy, noise and emissions targets. “The engine is on track with performance. We will now validate its inflight performance integrated with the aircraft,” says Dewar.

Pratt plans a series of minor improvements to the PW1500G to ensure initial CSeries will meet fuel-burn performance guarantees. The company has assembled 11 production engines at its Mirabel site, six of which are installed on the initial three CS100 test aircraft. Since flying the first PW1524G on its Boeing 747SP testbed in June 2011, Pratt has also begun testing the PW1200G for the Mitsubishi MRJ and PW1100G for the AirbusA320Neo, and says lessons learned from these engines will be applied to the CSeries.

“From Number 1 onward they have been full-up production engines,” says Bob Saia, vice president of commercial development programs for Pratt & Whitney. “They are just lagging some of the performance items that we have developed and some improvements we will make. We are targeting them for introduction in the last shipset of flight-test engines for the first CS300s,” he says, adding “We slowed the CSeries engine definition so suppliers can make the parts to the EIS configuration.”

The final service-entry standard will be introduced as a block change modification and includes “things associated with optimized cooling. We have turned down flow in some areas and pressurized some bleed cavities,” says Saia. As a result Pratt expects to pick up “a few tenths of a percent” of fuel-burn improvement. “That will put us right on our guarantee to Bombardier so we're on target for the first customer.”

Efforts are underway, meanwhile, to reduce the CSeries weight. “We have a small challenge, which is normal in development, so we are in a weight-saving mode,” says Dewar. “We plan to be on track with or better than all guarantees.”

With Guy Norris in Los Angeles.

See video and photos of the CSeries first flight on our Things With Wings blog at: ow.ly/p1xHL